It has already been known that dyes having a halogenotriazine group or a halogenopyrimidine group react with cellulose fibers in the presence of an acid-binding agent, and numerous dyes have been used actually as reactive dyes. These dyes are characterized in that they have a good wet fastness and light fastness and that dyeings therewith have an excellent brightness in color shade.
However, among reactive dyes for dip dyeing there have been no blue dyes with excellent fastnesses and brightness which are characteristics of this kind of dyes, and so it is intensively desired that such dyes which can dye cellulose fibers deep blue by dip dyeing method should be developed.